A federal judge has ruled that investigators can go through your Facebook profile if one of your friends gives them permission to do so. The decision, which is part of a New York City racketeering trial, comes as courts struggle to define privacy and civil liberties in the age of social media.

In an order issued on Friday, US District Judge William Pauley III ruled that accused gangster Melvin Colon can’t rely on the Fourth Amendment to suppress Facebook evidence that led to his indictment. Colon had argued that federal investigators violated his privacy by tapping into his profile through an informant who was one of this Facebook friends.

The informant’s Facebook friendship served to open an online window onto Colon’s alleged gangster life, revealing messages he posted about violent acts and threats to rival gang members. The government used this information to obtain a search warrant for the rest of Colon’s Facebook account. The Colon information is part of a larger investigation into crack-dealing and murder in the Bronx.

Judge Pauley III’s ruling is significant because it is the latest in a series of cases that defines how and when police can search social media.

In the Bronx case, the judge found that Colon couldn’t stop his Facebook friends doing what they liked with the information he revealed:

Colon’s legitimate expectation of privacy ended when he disseminated posts to his “friends” because those “friends” were free to use the information however they wanted-including sharing it with the Government.

To support this position, Judge Pauley III cited a case that confirmed the government can listen in on phone calls without a warrant provided that one of the people on the call gives it permission to do so.

Ironically, Colon’s current account suggests that the government’s ability to peruse Facebook profiles may have become even easier since the introduction of the Facebook Timeline. The feature can in some cases reveal past events and status updates to the public unless a user changes his or her privacy settings.

What appears to be Colon’s account (cited in the court case as “Mellymella Balla” in the Bronx) can now be seen by the public. Here is a screenshot from his profile:

The case may also raise the question of whether social media companies are providing an adequate explanation of their privacy settings to all Americans. You can read the ruling itself here: